Explorations of new second-order NLO materials in the AgI-MoVI/WVI-TeIV-O systems

Abstract

Explorations of new second-order NLO materials in the Ag^I-Mo^VI/W^VI-Te^IV-O systems led to three new mixed metal tellurites, namely, Ag₂Mo₃Te₃O₁₆, Ag₂MoTe₄O₁₂ and Ag₆W₃Te₄O₂₀. Ag₂Mo₃Te₃O₁₆ is isostructural with Na₂Mo₃Te₃O₁₆ and its structure features one-dimensional [Mo₃Te₃O₁₆]²⁻ anionic chains composed of [Mo₃O₁₄]¹⁰⁻clusters interconnected by [Te₃O₈]⁴⁻ anions via corner-sharing, such 1D chains are further interconnected by Ag⁺ ions into a 3D network. Ag₂MoTe₄O₁₂ is isostructural with Na₂MoTe₄O₁₂ and its structure features 3D anionic [MoTe₄O₁₂]²⁻ network with the Ag⁺ ions filling the cavities of the structure. Ag₆W₃Te₄O₂₀ belongs to a new structural type. Its structure composed of 1D [WO₂(TeO₃)₂]²⁻ anionic chains and 2D [W₂O₆(TeO₃)₂]²⁻ anionic layers, the above two types of anionic building units are interconnected by Ag⁺ ions into a 3D condensed network. Second harmonic generation (SHG) measurements indicate that Ag₂Mo₃Te₃O₁₆ displays a very large SHG response of approximately × 8 KDP. Band structure calculations based on DFT methods for all three compounds have also been performed.